BrickGen BrickGen is an AI-powered LEGO build generator. Upload a photo of any LEGO set box, describe what you want to build, and BrickGen will create a custom build concept — complete with a generated product image and a step-by-step illustrated instruction booklet — using only the pieces from that set.

How It Works Upload a photo of your LEGO set box Scan to automatically detect the set number, or type it manually Describe what you want to build Generate — BrickGen fetches your brick inventory from Rebrickable and uses Gemini AI to design a build concept and product image Follow the step-by-step instruction booklet with AI-generated images for each step Tech Stack Frontend

React 19 + Vite Custom CSS (no UI library) Backend

Python + FastAPI Google Gemini API (gemini-2.5-flash for text, gemini-3.1-flash-image-preview for images) Rebrickable API for LEGO part inventory Getting Started Prerequisites Node.js (v18+) Python 3.10+ A Google Gemini API key A Rebrickable API key Backend Setup

cd backend python -m venv .venv

Windows

.venv\Scripts\activate

macOS / Linux

source .venv/bin/activate

pip install -r requirements.txt Create a .env file in the backend/ directory:

GEMINI_API_KEY=your_gemini_api_key_here REBRICKABLE_API_KEY=your_rebrickable_api_key_here Start the server:

uvicorn genvision:app --reload The backend runs at http://localhost:8000.

Frontend Setup

cd frontend/lego-app npm install npm run dev The frontend runs at http://localhost:5173 and proxies all /api requests to the backend.

API Endpoints Method Endpoint Description POST /api/analyze-set Extract set number from an uploaded box image POST /api/generate-build Generate a build concept and product image POST /api/generate-steps Generate step-by-step building instructions POST /api/generate-step-image Generate an illustration for a single step Project Structure

legosetgenerator/ ├── backend/ │ ├── genvision.py # FastAPI app and route handlers │ ├── lego_ideas.py # Gemini and Rebrickable integrations │ ├── requirements.txt │ └── .env.example └── frontend/ └── lego-app/ ├── src/ │ ├── App.jsx # Main React component │ └── App.css ├── vite.config.js └── package.json Environment Variables Variable Description GEMINI_API_KEY Google Gemini API key for AI generation REBRICKABLE_API_KEY Rebrickable API key for LEGO part data Never commit your .env file. Use .env.example as a template.